page_height = document.body.scrollHeight;
page_height ='height: ' + page_height + 'px';


var bg_line_height = document.createElement("style"); 
document.head.appendChild(bg_line_height); 
sheet = bg_line_height.sheet; 
sheet.addRule('.line::before', page_height);

var bg_image_height = document.createElement("style"); 
document.head.appendChild(bg_image_height); 
sheet = bg_image_height.sheet; 
sheet.addRule('.content::after', page_height);